a pencil graphite electrode modified by carbon nano-onions and graphene nanoplate for trace determination of olanzapine

Abstract: stress is the body's way of responding to any kind of demand or threat which can cause a variety of disorders, especially, when it is followed by danger or fear. several types of drugs have been used for the therapy of stress. olanzapine (olp), 2-methyl-4-(4-methyl-1- 41 piperazinyl)-10h-thieno-[2,3-b] benzodiazepine, is a thienobenzodiazepine derivative which has the most application for the stress treatment. olanzapine has been widely used as antimigraine and antidepressant. some side effects such as drowsiness, dizziness, lightheadedness, stomach upset, dry mouth and constipation can be serious through the high prescription of olp. thus, the monitoring of olp concentration in biological fluid for therapeutic drug monitoring purposes is very important. in this study, a modified pencil graphite electrode (pge) modified with the carbon nano-onions (cnos) and graphene nanoplate (gnp) was used for the measurement of olp by differential pulse voltammetry (dpv) technique. the electrochemical studies revealed the modified electrode is capable of the voltametric determination of traces of olp in the phosphate buffer at a working potential of 0.2 v (vs. ag/agcl). the surface morphology and electrical properties of the modified electrode were characterized by scanning electron microscopy (sem) and electrochemical impedance spectroscopy (eis). to obtain the great efficiency of the sensor some experimental factors such as time, the potential of accumulation and ph value of the electrolyte were optimized. the modified pge under optimized conditions represented a linear range of 1.0×10-10_ 4.5×10-8 m and a detection limit of 5.4×10-11 m. these satisfactory results can be attributed to utilizing the cnos and gnp in the electrode modification process due to some of its admirable characterizations of this nanostructure including high surface area, excellent electrical conductivity and good electrocatalytic activity. consequently, the developed sensor was applied for the determination of olp in real samples such as pharmaceutical tablet blood serum samples.